This is branched from !609 (merged) which should be merged first.
So far, just pops up a modal that is draggable with "Not yet supported" text where the extension should be rendered. To do: hook up with the proof-of-concept extension by @bnjmnm after both are merged.
This MR implements a new reduxSlice which contains an activeExtension which has a few simple properties about a given extension that can hopefully be used to determine when/which extension to render. This hopefully works/is suitable but if not, it's easy enough to augment it or even replace it when it comes to the actual integration with the extension P.o.C
It extends the Dialog component that Balint already made with an extra modal
boolean prop